Single-case experimental designs
True or false
A reversal design (ABA) can be greatly improved by extending it to an ABAB design or even an ABABAB design.
True.
True or false
One-group posttest-only design is an example of a reversal design.
False.
One-group posttest-only design is a quasi-experimental design.
Developmental psychologists often study the ways that individuals change as a function of this.
In all cases, the major variable is ____?
Age
In developmental research using a cross-sectional approach, differences among age groups attributed to social, cultural, economic, or political differences rather than to the effect of age.
Cohort effects
A group of people born at about the same time and exposed to the same societal events; ____ effects are confounded with age in a cross-sectional study.
Cohort
True or False.
Single-case designs are useful for studying many research problems and should be considered a powerful alternative to more traditional research designs.
They can be especially valuable for someone who is applying some change technique in a natural environment.
True
This type of research design employs a separate control group, but the participants in the two conditions—the experimental group and the control group—are not equivalent.
The differences become a confounding variable that provides an alternative explanation for the results. This problem, called selection differences or selection bias, usually occurs when participants who form the two groups in the experiment are chosen from existing natural groups.
Nonequivalent Control Group Design
This method is a compromise between the longitudinal and cross-sectional methods.
Sequential Method
As a threat to internal validity, the possibility that a change in the characteristics of the measurement instrument, including human observers, is responsible for the results.
Instrument Decay
A type of effect, within a quasi-experimental design, naturally occurring change within the individual is responsible for the results.
Maturation effect
The basic issue in single-case experiments is how to determine that the manipulation of the independent variable had an effect. One method is to demonstrate the reversibility of the manipulation.
A simple ______ design takes the following form:
A (baseline period) → B (treatment period) → A (baseline period).
Reversal Design
One way to improve the interrupted time series design is to find some kind of control group with this type of research design.
Control Series Design
This method shares similarities with the independent groups design.
Cross-Sectional Method
Differences in the type of subjects who make up each group in an experimental design. One way such differences can arise is by allowing participants to choose which group they will be assigned to.
Selection Differences or Selection Bias
A type of effect, potential threat to internal validity, any outside event that could be responsible for the results.
History effects
Single-case experimental designs have traditionally been called single-subject designs; an equivalent term you may see is ______ N designs.
N=population
n=sample size
small
In the one-group pretest-posttest design, identify 3 of the 5 potential threats to internal validity:
1. History Effects
2. Maturation Effects
3. Testing Effects
4. Instrument Decay
5. Regression toward the mean aka statistical regression.
The longitudinal method is similar to this type of design.
Repeated measures design.
A quasi-experimental design in which nonequivalent groups are used, but a pretest allows assessment of equivalency and pretest-posttest changes.
Nonequivalent control group pretest-posttest design
The principle that extreme scores on a variable tend to be closer to the mean when a second measurement is made.
Regression toward the mean
In a multiple baseline design, the effectiveness of the treatment is demonstrated when a behavior changes only after the manipulation is introduced. To demonstrate the effectiveness of the treatment, such a change must be observed under multiple circumstances to rule out the possibility that other events were responsible.
Variations of this design include:
across subjects
across behaviors
across situations
Multiple Baseline Design
Internal validity is of concern with this type of quasi-experimental design.
One-group posttest-only design
The first phase of this method begins with the cross-sectional method; for example, you could study groups of 25- and 35-year-olds. These individuals are then studied using the longitudinal method with each individual tested at least one more time.
Sequential Method
A method of pairing individuals for assignment to a treatment and control condition based upon a combination of scores on participant variables.
Propensity Score Matching
This type of research design examines the dependent variable over an extended period of time, before and after the independent variable is implemented
•Vulnerable to interpretation problems (possible regression to the mean).
Interrupted time series design